BackgroundFree tissue transfers performed in patients with hematological diseases represent significant challenges for micro‐surgeons. There are rare literatures that address the outcome in these patients. Therefore, we collected our database, analyzed the outcome, reliability, and related‐management of microsurgical technique in the patients with hematological diseases.MethodsA retrospective chart review of 20 patients with hematological disorders who received free tissue transfers during 20‐years period in a single microsurgical center was done. Eleven patients who received head and neck reconstruction were found to have hyperfibrinogenemia. Seven patients with reactive thrombocytosis after trauma, and two patients with leukemia had soft tissue defects in the upper and lower extremities. Twenty‐six flaps were used for free tissue transfers. Intra‐operatively all patients received intravenous 5,000 Ud of heparin post immediate reperfusion. Anti‐coagulant medication such as Dextran‐40 or prostaglandin‐E1 (PGE1) was given postoperatively.ResultsTwenty‐three of the 26 free flaps survived without vascular compromise. Intra‐operatively all patients received intravenous 5,000 Ud of heparin post immediate reperfusion, and anti‐coagulant medication such as Dextran‐40 or prostaglandin‐E1 was given to the patients postoperatively. The three failed cases were found in patients with hyperfibrinogenemia and needed further reconstruction with another flap. The overall success rate was 88.5% (23/26).ConclusionsHematologic disorder is not a predicted factor of free flap failure. The key factors for success flap survival in patients with hematologic disorders include preoperative knowledge of the medical condition and monitoring potential post‐operative complications, aggressive hematologist consultations, and meticulous non‐traumatic surgical anastomosis. © 2014 Wiley Periodicals, Inc. Microsurgery 34:505–510, 2014.